It is not known when the name Brookhouse first appeared. Brookhouse is composed of two Anglo-Saxon (Old English) words, brōc (brook/stream) and hūs (house). 
The first ‘house by the brook’ was probably on the site of the current Brookhouse Old Hall, which was built in 1713 beside the Bull Beck.
What is now called Brookhouse was once the centre of Caton township. Caton included several hamlets, such as Town End and Caton Green.
The old Roman road heading east from Lancaster up the Lune Valley ran by Old Hall Farmhouse near the centre of modern Brookhouse and on to Caton Green.
In the late 1700s and early 1800s the centre of Caton shifted to Town End. This was because of the nearby industrial mills and also the new  turnpike road along the Lune Valley (now the A683). 
So, when the Post Office decided that Caton had become too spread out for them, it was Town End that became officially Caton and the old village centre was named Brookhouse.